Hyaluronic acid is a biologically synthesized natural substance abundant in the skin, etc, of animals, Hyaluronic acid is also called hyaluronan. It is hydrophilic because it has many hydroxyl (—OH) groups and is involved in skin moisturization. It also regulates various physiological actions by reacting with the CD44 protein expressed in various epithelial cells.
Skin is an organ which is constantly in contact with outside. It is composed of three layers of the epidermis, the dermis and the subcutaneous tissue from outside and protects the human body from physical and/or chemical stimuli from outside. Especially, the skin plays an important role of controlling loss of water, which accounts for about 65-70% of the human body, transports various physiologically active substances necessary for the human body and maintains soft and moist states, out of the human body.
However, with aging, the skin intrinsically experiences decreased secretion of various hormones regulating metabolism as well as decreased biosynthesis of immunoproteins and biological proteins necessary for the body due to decreased function of immune cells and cellular activity. Extrinsically, due to increased UV radiation caused by the destruction of the ozone layer and aggravated environmental pollution, the function and aesthetic beauty of the skin decline owing to increase in free radicals, harmful reactive oxygen species, etc.
Therefore, researches are being actively carried out on substances with superior efficacy for improving skin and safety. In addition, researches are being actively carried out on substances which improve skin condition through external application such as cosmetics and provide skin-improving effect through dietary intake.
In this regard, interests are consistently increasing in natural plant materials exhibiting skin-improving effect. Because many natural plant materials have shown proven safety or effect throughout use for hundreds of years, they are advantageous in terms of safety and environment friendliness.
Accordingly, there is a need for a substance which is effective in improving skin and is safe.